(a) Field of the Invention
The present invention relates to a rail support adjusting and fastening device which is used in such a state that tilting of each of the rails and the gage of a track are briefly adjusted in advance by means of connecting members such as cross ties for connecting parallel rails to one another when the track is directly laid onto a concrete bed as a direct fastened track.
(b) Description of the Prior Art
As a rail support device, which is used independently, for the parallel rails in laying a direct fastened track, such a rail support device has been proposed as shown in FIGS. 6 and 7. Namely, a rail support device a is constructed as follows. A support plate e is made to present a rectangular shape and provides a support surface portion d for supporting a bottom portion c of a rail b. A screw hole f is formed respectively with both of the inside and outside portions of the support plate e to extend vertically. A support bolt h is formed to have an upper screw portion g at the upper portion thereof and formed to be a tapered bar at the lower portion thereof to slender gradually in a direction of the lower end thereof. The support bolt h is screwed with the screw hole f by means of the upper screw portion g. The height of the support plate may be adjusted by changing the screwing conditions of the support bolt h. An inside portion and an outside portion of upper surfaces m of the bottom portion c may be pressed by means of a forward end pressing portion k of each of pressing washers j in such a manner that nuts i screwed with the upper screw portions g of the support bolts h, press the pressing washers j. With the pressing of the pressing washers j, the rail support device a may be integral with the rail b.
As shown in FIG. 8, the rail support device a as constructed above, may be mounted respectively on the parallel rails b in opposite positions in such a state that the gage and tilting of the rails b have been adjusted briefly in advance. Thus, height and low of the rails and cant or superelevation of the outer rail at turning points have been adjusted in cooperation with both the rail support devices a.
However, according to the above-mentioned rail support devices, it cannot support and fix a skeleton of track o stably, and therefore, the following problems have occurred. Namely, it is very difficult to carry out an adjusting operation precisely. Further, its adjusting operation is inefficient and laying cost of a direct fastened tract becomes high and a long period is required for laying the direct fastened tract.
Now, the above mentioned problems will be described in detail below together with their causes.
The above-mentioned rail support device involves the following unstable factors (A).about.(C)X:
(A) It is difficult to manufacture the under surface p of the rail bottom portion c to be plane perfectly and also it is practically impossible to finish the support surface d of the support plate to be plane perfectly. Therefore, where the rail bottom c is supported by the support surface d, perfect face to face contact cannot be obtained between the support surface d and the under surface p of the rail bottom c. Namely, the contact state between the support surface d and the under surface p does not become a contact state at a position which is the best for perfect fixing of the skeleton of the track, but it becomes the unstable contact state wherein the contact portions of the surfaces p and d may easily be varied under the influence of the pressing conditions of the pressing washers and external forces.
(B) Further, since the upper surfaces m of the rail bottom c are finished in the same manner as that of the under surface p of the rail bottom, where the pressing washers j are pressed by means of the pressing nuts i, the pressing portions k present a state of plane contact, line contact or sometimes spot contact according to the pressing conditions of the pressing nuts i. In anycase, it is difficult to say that the pressing portions are fixed. Particularly, where the pressing washers are made thin, it tends to present an unstable spot pressing state since the pressing washers may easily be bent or deformed.
(C) Additionally, since the support bolt h is screwed with both sides of the support plate e respectively, it is practically impossible to adjust the four support bolts h of both of the rail support devices, which are opposite to each other, to be in such a screwed state that all of the support bolts h receive an equal load. Therefore, referring to each of the rail support devices, any one of the support bolts (two support bolts in total) supports the load of the skeleton of track mainly.
Since the conventional rail support device includes the above mentioned unstable factors, where the device is mounted on the skeleton of the track by setting the rail bottom portion c on the support surface portion of the support plate e and pressing the pressing washer j by means of the pressing nut i, the supporting condition of the rail is varied unstably under the influence of external forces such as adjusting works of adjacent support devices and vibrations at the time of concrete deposition, though the rail bottom portion c is being supported by the support surface portion d. As the result, each of the rail support devices mounted on the rail, continues always to be under unstable conditions and it is impossible to adjust height and low of the skeleton of the track or cant correctly and fix the skeleton of the track completely in a predetermined place.
Therefore, when laying a track by using the conventional rail support devices, prior to concrete deposition of the concrete bed, it was necessary to fix the skeleton of the track supplementally by utilizing a number of auxiliary members under the state that the skeleton of the track was supported by the rail support devices.
Thus, in such a conventional method for fixing the skeleton of the track by using a number of auxiliary members, there occurred not only a problem that it was difficult to lay a track with high precision due to increase of the unstable factors, but also problems that it took a lot of time for the auxiliary works and that its track laying efficiency became down and needed a long term of works so that its laying cost increased.